Generic-type rotors have been known for a long time from the general prior art. As is known, the rotor disks which are used in the rotor carry rotor blades, which are arranged in a ring, on their outer sides, by means of which an operating medium is compressible or by means of which the energy which is contained in an operating medium can be converted into the rotational movement of the rotor. The stacked rotor disks, which abut against each other, in this case are clamped to each other by at least one tie rod. For this purpose, the tie rod extends through the rotor disks and is pretensioned by means of nuts which are screwed on at the ends. The tie rod ensures the tight abutting of the rotor disks against each other.
It is further known from DE 199 14 227 B4 that a welded-together rotor can have an outer, drum-like, thermal protective cover for protecting the internal region of the rotor.
In addition, a cooled gas turbine rotor is known from patent specification DE 898 100. Its outer periphery is formed by annular blade carriers which are provided with oppositely-disposed recesses towards the axis. In each of these recesses a projecting edge of a rotor disk engages in each case so that the respective blade carrier is clamped in a form-fitting manner between two rotor disks.
Furthermore, a drum rotor,—which is assembled from a plurality of parts, for gas turbines is known from patent specification CH 238 207. The drum rotor in this case comprises drum which is axially assembled from a plurality of rings which are welded to each other on the outer drum periphery at the abutment points. In this case, the edge of a rotor disk is enclosed in a form-fitting manner between two adjacent rings in the region of the abutment points.
A modular rotor for a turbomachine in disk type of construction is known from patent specification DE 972 310. The rotor blades which are carried by the rotor are fastened in detail on rings. The rings by their end faces are retained by means of form fit by rotor disks which are arranged on both sides.
According to general efforts to increase efficiency and output of gas turbines which are used for generating energy, comparatively large compressor mass flows with simultaneously high compressor pressure ratios are required. Greater compressor mass flows occur for example in the case of compressors of gas turbines, the nominal output of which is more than 50 MW. The compressor pressure ratio is greater than 1:16 in this case. On account of the comparatively high pressure ratio the temperature of the compressed air rises to several hundred degrees Celsius. The high air temperature heats up the adjacent elements of the compressor, especially in the region of the rear compressor stages, so that nowadays the previously used materials can no longer adequately withstand the temperatures which occur now on account of the increased pressure ratios. When using more temperature-resistant materials for rotor disks, however, further disadvantages in strength and machinability emerge on account of the overall size of compressors with large mass flows so that these materials are suitable only to a limited extent and can be used only to a limited extent. Moreover, the more temperature-resistant materials are also more expensive.